井下配电网络必须用（）短路电流，校验开关设备。
A.三相
B.两相
C.两相接地
D.最小
参考答案：A
重介旋流器定压给料箱的用途？
Choose the words and fill in the blanks. 选词填空。
A: May I (help, helping) you?
B: Yes! I want to buy a (dress, dresses). Where are the (dress, dresses)?
A: I'll (show, shows) you. This (way, dress), please. Here they (is, are)!
B: Thanks!
